diff --git a/m4/cares-functions.m4 b/m4/cares-functions.m4
index 250b5451..8fc25a6d 100644
--- a/m4/cares-functions.m4
+++ b/m4/cares-functions.m4
@@ -16,7 +16,7 @@
 #***************************************************************************
 
 # File version for 'aclocal' use. Keep it a single number.
-# serial 15
+# serial 17
 
 
 dnl CARES_INCLUDES_ARPA_INET